Low-temperature pump helium mass spectrometer leak detection device and low-temperature pump leak detection method

Abstract

The present application relates to the field of cryogenic pump leak detection, and discloses a cryogenic pump helium mass spectrometric leak detection device and a cryogenic pump leak detection method, the cryogenic pump helium mass spectrometric leak detection device comprising: a leak detection cabin, a vacuum pumping assembly, a helium detection assembly, a first vacuum degree detection piece, a cryogenic pump body detection assembly, a helium filling assembly, a helium concentration detection piece, a first calibration assembly, and a second calibration assembly, the vacuum pumping assembly comprising a first pipeline, a first valve, a second valve, a first vacuum pump, and a second vacuum pump; the helium detection assembly comprising a second pipeline, a third valve, and a helium mass spectrometric leak detector; the cryogenic pump body detection assembly comprising a third pipeline, a second vacuum degree detection piece, a fourth pipeline, and a fourth valve; and the helium filling assembly comprising a fifth pipeline, a helium storage piece, and a fifth valve.The cryogenic pump helium mass spectrometric leak detection device can simultaneously complete leak detection of the refrigerator and the cryogenic pump body in one operation, thereby improving leak detection efficiency.

Description

Technical Field

[0001] This invention relates to the field of cryogenic pump leak detection technology, and in particular to a cryogenic pump helium mass spectrometry leak detection device and a cryogenic pump leak detection method. Background Technology

[0002] Large-scale scientific projects such as magnetic confinement fusion rely on cryogenic pumps to maintain extremely high vacuum, and before delivery, they need to undergo cryogenic testing at conditions better than 1×10⁻⁶. -9 Pa.m 3 / s vacuum leak detection.

[0003] The core challenge in leak detection of cryogenic pumps lies in the duality of their leakage sources. One source is the leakage of high-pressure helium from inside the GM refrigerator (pressure leak), which requires detection using the pressure-vacuum method. The other source is the leakage from the external atmosphere into the internal vacuum chamber of the cryogenic pump (vacuum leak), which requires detection using the helium shroud method.

[0004] Generally, GM cryogenic pumps often use a separate pressure-vacuum method for leak detection. This method is usually implemented at room temperature: the high-pressure helium circuit of the cryogenic pump's cold head is charged to the rated pressure and placed in a vacuum chamber. The leak of helium from the circuit into the vacuum chamber is detected to determine its sealing performance. However, this method is completely divorced from the actual operating conditions of the cryogenic pump and cannot reflect the changes in sealing performance caused by thermal stress of materials in extremely low-temperature environments (such as "cold leaks" or "cold welds"), resulting in leak detection results that are seriously inconsistent with the actual sealing condition. Secondly, this method can only detect internal leaks in the cryogenic pump's own circuit and cannot cover the sealing performance of the connection interfaces (such as flanges, pipe interfaces, etc.) after the cryogenic pump is assembled. It is easy to miss key potential leak points in the system integration, resulting in a serious blind spot in the overall sealing reliability assessment.

[0005] For cryogenic pump bodies, the overall helium shroud method is commonly used for leak detection. This method involves completely enclosing the pump body with a large plastic film shroud and filling it with helium gas. A helium mass spectrometer leak detector connected to the pump inlet is then used to detect the helium signal seeping in from the outside, thereby determining the overall leak rate. However, this method suffers from difficulties in maintaining a stable helium concentration within the large helium shroud and its uneven spatial distribution, leading to a significant decrease in leak detection sensitivity. Furthermore, the helium shroud itself is expensive and the operation process is cumbersome, further limiting its application efficiency and reliability.

[0006] Understandably, current technologies only allow for step-by-step, offline testing of the GM refrigerator and the cryogenic pump body: the GM refrigerator is tested separately first, then the entire pump is assembled and tested. This approach has two major drawbacks: first, the process is cumbersome and time-consuming, requiring two sets of tooling, resulting in extremely low efficiency; second, once a leak is detected in the entire pump, it is difficult to quickly pinpoint whether the leak originates from the GM refrigerator or the cryogenic pump body itself, easily leading to misjudgments and high maintenance costs; and third, it does not consider the helium leak detection process under the actual operating conditions of the GM refrigerator, which may result in leak detection problems.

[0007] Therefore, there is an urgent need to develop an integrated leak detection solution that can quickly switch between testing the two core components of a cryogenic pump in one go, in order to overcome the inherent defects of traditional methods such as low efficiency and insufficient reliability. Summary of the Invention

[0008] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of the present invention is to provide a cryogenic pump helium mass spectrometry leak detection device, which can perform leak detection on both the refrigerator and the cryogenic pump body in a single unit, thereby improving leak detection efficiency.

[0009] The present invention also aims to provide a leak detection method for cryogenic pumps, using the aforementioned cryogenic pump helium mass spectrometry leak detection device.

[0010] A cryogenic pump helium mass spectrometry leak detection device according to an embodiment of the present invention includes: a leak detection chamber for placing a cryogenic pump to be detected; a vacuum pumping assembly, the vacuum pumping assembly including a first pipeline, a first valve, a second valve, a first vacuum pump, and a second vacuum pump, one end of the first pipeline being connected to the leak detection chamber, and the other end being connected to the first vacuum pump, wherein the first valve, the second vacuum pump, and the second valve are sequentially connected in series on the first pipeline in the direction extending from the leak detection chamber to the first vacuum pump; a helium detection assembly, the helium detection assembly including a second pipeline, a third valve, and a helium mass spectrometer leak detector, one end of the second pipeline being connected to the portion of the first pipeline located between the second vacuum pump and the second valve, and the other end being connected to the helium mass spectrometer leak detector, the third valve being sequentially connected in series on the second pipeline; a first vacuum degree detection element, the first vacuum degree detection element being connected to the leak detection chamber; and a cryogenic pump body detection assembly, the cryogenic pump body detection assembly including a third pipeline, a second vacuum degree detection element, and a fourth... The system includes a pipeline and a fourth valve. The third pipeline is located inside the leak detection chamber and extends one end to the outside of the leak detection chamber, connecting to the second vacuum level detection element. The other end of the third pipeline inside the leak detection chamber is configured to connect to the cryogenic pump body. The fourth pipeline is located inside the leak detection chamber and connects one end to the third pipeline, while the other end extends to the outside of the leak detection chamber and connects to the portion of the first pipeline located between the first valve and the second vacuum pump. The fourth valve is connected in series on the fourth pipeline. A helium filling assembly includes a fifth pipeline, a helium storage element, and a fifth valve. One end of the fifth pipeline connects to the leak detection chamber, and the other end connects to the helium storage element. The fifth valve is connected in series on the fifth pipeline. A helium concentration detection element connects to the leak detection chamber. A first calibration assembly includes a sixth valve and a first calibration leak hole connected to the leak detection chamber via the sixth valve. A second calibration assembly includes a seventh valve and a second calibration leak hole connected to the third pipeline via the seventh valve.

[0011] The cryogenic pump helium mass spectrometry leak detection device according to embodiments of the present invention, through components such as a leak detection chamber, a vacuum pumping assembly, a helium detection assembly, a first vacuum degree detection element, and a cryogenic pump body detection assembly, can perform leak detection on the refrigerator and the cryogenic pump body in one device and one vacuum pumping process. It can detect both high-pressure helium leaks inside the refrigerator and vacuum leaks in the cryogenic pump vacuum chamber and system connection interfaces. Compared to traditional distributed, offline leak detection methods, it can improve leak detection efficiency. Moreover, the detection process can simulate the actual cryogenic pump operating conditions for system-level leak detection, thus improving leak detection accuracy. Simultaneously, the integrated tooling replaces the bulky and cumbersome traditional helium shroud, significantly reducing helium consumption and tooling costs, improving operational economy and convenience.

[0012] In some embodiments of the invention, the leak detection chamber includes a shell and an end cap, the top of the shell having an opening, the end cap being detachably disposed over the opening, and the shell being configured for mounting the cryogenic pump to be tested.

[0013] In some embodiments of the present invention, the end cap is provided with a first hole and a third hole, and the chamber is provided with a second hole, a fourth hole, a fifth hole, a sixth hole, and a seventh hole; wherein, the first pipeline is installed in the first hole, the first vacuum degree detection element is connected to the second hole, the third pipeline is installed in the third hole, the fourth pipeline is installed in the fourth hole, the fifth pipeline is installed in the fifth hole, the helium concentration detection element is connected to the sixth hole, and the sixth valve is connected to the seventh hole.

[0014] In some embodiments of the present invention, the cabin is provided with an eighth hole and a ninth hole, the compressor of the cryogenic pump is located outside the cabin, the compressor is provided with an inlet pipe and a return pipe, the inlet pipe passes through the eighth hole and is connected to the air inlet of the refrigeration unit, and the return pipe passes through the ninth hole and is connected to the air return port of the refrigeration unit.

[0015] In some embodiments of the present invention, the helium filling assembly further includes a pressure reducing valve, which is connected in series on the portion of the fifth pipeline located between the helium storage unit and the fifth valve.

[0016] In some embodiments of the present invention, the first vacuum pump is a mechanical pump and the second vacuum pump is a molecular pump.

[0017] In some embodiments of the present invention, the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, and the seventh valve are solenoid valves.

[0018] In some embodiments of the present invention, the first vacuum degree detection element and the second vacuum degree detection element are vacuum gauges.

[0019] According to an embodiment of the present invention, a leak detection method for a cryogenic pump is also provided. The method includes: performing a leak detection of the cryogenic pump, wherein the steps of the leak detection include: ensuring that all valves are in a normally closed state, and that the first vacuum level detection device, the first vacuum pump, the helium mass spectrometer leak detector, and the cryogenic pump are in normal working condition; opening the first valve and the second valve to reduce the vacuum level in the leak detection chamber to a first threshold; detecting the vacuum level in the leak detection chamber using the first vacuum level detection device; and when the detected vacuum level in the leak detection chamber is less than the first threshold, opening the second vacuum pump to reduce the vacuum level in the leak detection chamber. When the vacuum level in the leak detection chamber drops to a second threshold, which is less than the first threshold, the second valve is closed and the third valve is opened simultaneously. The first detection data in the leak detection chamber is then detected using the helium mass spectrometer leak detector. The sixth valve is opened to activate the first calibration leak hole, and the first calibration data is acquired. The sixth valve is closed, and after the cryogenic pump helium mass spectrometer leak detection system stabilizes, the first stable data is acquired. The leak rate of the refrigerator is calculated based on the first detection data, the first calibration data, and the first stable data. The leak detection of the refrigerator is completed. Afterwards, a leak test is performed on the cryogenic pump body. The steps of the cryogenic pump body leak test include: closing the first valve, the third valve, the second vacuum pump, and the refrigerator; opening the fifth valve to allow helium from the helium storage device to fill the leak detection chamber, detecting the helium concentration in the leak detection chamber using the helium concentration detector, and closing the fifth valve again when the helium concentration in the leak detection chamber reaches a third threshold; opening the second valve and the fourth valve, and detecting the vacuum level inside the cryogenic pump body using the second vacuum level detector; when the vacuum level inside the cryogenic pump body drops to the first threshold, opening the... The second vacuum pump reduces the vacuum level inside the cryogenic pump body to the second threshold. When the vacuum level inside the cryogenic pump body reaches the second threshold, the second valve is closed and the third valve is opened. The second detection data inside the cryogenic pump body is detected by the helium mass spectrometer leak detector. The seventh valve is opened to activate the second calibration leak hole and acquire the second calibration data. The seventh valve is closed, and after the cryogenic pump helium mass spectrometer leak detection device system stabilizes, the second stable data is acquired. The leak rate of the cryogenic pump body is calculated based on the second detection data, the second calibration data, and the second stable data.

[0020] According to the leak detection method for cryogenic pumps of this invention, by substituting first detection data, first calibration data, first stabilization data, and first helium concentration value into the leak rate calculation formula, the computer processing system ultimately calculates the actual leak rate of the refrigerator. Similarly, by substituting second detection data, second calibration data, second stabilization data, and second helium concentration value into the leak rate calculation formula, the computer processing system ultimately calculates the actual leak rate of the cryogenic pump body, thereby improving detection efficiency and accuracy. Furthermore, during the sequential leak detection of the refrigerator and cryogenic pump body, the leak detection chamber is evacuated only once, further improving leak detection efficiency.

[0021] In some embodiments of the present invention, the first detection data includes the background value and background noise detected in the leak detection chamber by the helium mass spectrometer leak detector; the first calibration data is the stable signal value generated by the first calibration leak hole; the first stable data is the final value measured after the cryogenic pump helium mass spectrometer leak detection device system has stabilized; the second detection data includes the background value and background noise detected in the cryogenic pump body by the helium mass spectrometer leak detector; the second calibration data is the stable signal value generated by the second calibration leak hole; the second stable data is the final value measured after the cryogenic pump helium mass spectrometer leak detection device system has stabilized.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0024] Figure 1 This is a schematic diagram of the structure of a cryogenic pump helium mass spectrometry leak detection device used in conjunction with a cryogenic pump for leak detection, as provided in some embodiments of the present invention.

[0025] Figure 2 A three-dimensional structural schematic diagram of the leak detection chamber provided in some embodiments of the present invention;

[0026] Figure 3 A cross-sectional view showing the cooperation between a leak detection chamber and a cryogenic pump as provided in some embodiments of the present invention;

[0027] Figure 4 This is a flowchart of a leak detection method for a cryogenic pump according to some embodiments of the present invention;

[0028] Figure 5 This is a flowchart of a leak detection method for a cryogenic pump according to a specific embodiment of the present invention.

[0029] Figure label:

[0030] 100. Cryogenic pump helium mass spectrometry leak detection device;

[0031] 10. Leak detection chamber; 11. Hull; 11a. Opening; 11b. Second hole; 11d. Fifth hole; 11e. Sixth hole; 11f. Seventh hole; 11g. Eighth hole; 11h. Ninth hole; 12. End cap; 12a. First hole; 12b. Third hole;

[0032] 20. Vacuum pumping assembly; 21. First pipeline; 22. First valve; 23. Second valve; 24. First vacuum pump; 25. Second vacuum pump;

[0033] 30. Helium detection assembly; 31. Second pipeline; 32. Third valve; 33. Helium mass spectrometer leak detector;

[0034] 40. First vacuum degree detection component;

[0035] 50. Cryogenic pump body testing assembly; 51. Third pipeline; 52. Second vacuum degree testing component; 53. Fourth pipeline; 54. Fourth valve;

[0036] 60. Helium filling assembly; 61. Fifth pipeline; 62. Helium storage unit; 63. Fifth valve; 64. Pressure reducing valve;

[0037] 70. Helium concentration detection device; 80. First calibration assembly; 81. Sixth valve; 82. First calibration leak; 90. Second calibration assembly; 91. Seventh valve; 92. Second calibration leak;

[0038] 200. Cryogenic pump; 210. Refrigeration unit; 220. Cryogenic pump body; 230. Compressor; 231. Inlet pipe; 232. Return pipe. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] Furthermore, features specified as "first" or "second" may explicitly or implicitly include one or more of the same feature, used to distinguish and describe features, without any order or distinction of importance.

[0042] In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] The following is for reference. Figures 1-3 The following describes a cryogenic pump helium mass spectrometry leak detection device 100 according to an embodiment of the present invention.

[0045] like Figure 1 As shown, the cryogenic pump helium mass spectrometry leak detection device 100 of this embodiment includes: a leak detection chamber 10, a vacuum pumping assembly 20, a helium detection assembly 30, a first vacuum degree detection element 40, a cryogenic pump body detection assembly 50, a helium filling assembly 60, a helium concentration detection element 70, a first calibration assembly 80, and a second calibration assembly 90.

[0046] The leak detection chamber 10 is used to house the cryogenic pump 200 to be tested. The vacuum assembly 20 includes a first pipe 21, a first valve 22, a second valve 23, a first vacuum pump 24, and a second vacuum pump 25. One end of the first pipe 21 is connected to the leak detection chamber 10, and the other end is connected to the first vacuum pump 24. In the direction from the leak detection chamber 10 to the first vacuum pump 24, the first valve 22, the second vacuum pump 25, and the second valve 23 are sequentially connected in series on the first pipe 21. The helium detection assembly 30 includes a second pipe 31 and a third valve 25. 2. A helium mass spectrometer leak detector 33 is connected to the first pipeline 21, with one end of the second pipeline 31 connected to the portion of the first pipeline 21 located between the second vacuum pump 25 and the second valve 23, and the other end connected to the helium mass spectrometer leak detector 33. A third valve 32 is connected in series on the second pipeline 31. A first vacuum degree detection element 40 is connected to the leak detection chamber 10. The cryogenic pump body detection assembly 50 includes a third pipeline 51, a second vacuum degree detection element 52, a fourth pipeline 53, and a fourth valve 54. The third pipeline 51 is located inside the leak detection chamber 10 and one end of the third pipeline 51 is connected to the first pipeline 21 located between the second vacuum pump 25 and the second valve 23. The third pipe 51 extends to the outside of the leak detection chamber 10 and connects to the second vacuum level detection element 52. The other end of the third pipe 51 located inside the leak detection chamber 10 is configured to connect to the cryogenic pump body 220. The fourth pipe 53 is located inside the leak detection chamber 10, with one end connected to the third pipe 51 and the other end extending to the outside of the leak detection chamber 10 and connecting to the portion of the first pipe 21 located between the first valve 22 and the second vacuum pump 25. The fourth valve 54 is connected in series on the fourth pipe 53. The helium filling assembly 60 includes a fifth pipe 61. The system includes a helium storage unit 62 and a fifth valve 63. One end of the fifth pipeline 61 is connected to the leak detection chamber 10, and the other end is connected to the helium storage unit 62. The fifth valve 63 is connected in series on the fifth pipeline 61. The helium concentration detection unit 70 is connected to the leak detection chamber 10. The first calibration component 80 includes a sixth valve 81 and a first calibration leak hole 82 that is connected to the leak detection chamber 10 through the sixth valve 81. The second calibration component 90 includes a seventh valve 91 and a second calibration leak hole 92 that is connected to the third pipeline 51 through the seventh valve 91.

[0047] The leak detection chamber 10 can refer to a closed box used to house the cryogenic pump 200 to be tested. The material can be, but is not limited to, alloy steel, stainless steel, aluminum alloy, and composite materials, etc.

[0048] The vacuum pumping assembly 20 refers to the assembly that evacuates the leak detection chamber 10, bringing the internal pressure of the leak detection chamber 10 to a negative pressure state. In the above technical solution, the vacuum pumping assembly 20 includes a first pipeline 21, a first valve 22, a second valve 23, a first vacuum pump 24, and a second vacuum pump 25. The first valve 22 and the second valve 23 can be, but are not limited to, solenoid valves, manual valves, or other types of control valves. The first vacuum pump 24 and the second vacuum pump 25 can refer to pumps capable of performing vacuum evacuation, wherein the second vacuum pump 25 is configured to have a greater vacuum evacuation capacity than the first vacuum pump 24, enabling the achievement of higher vacuum requirements. In the above example, the first vacuum pump 24 and the second vacuum pump 25 can be, but are not limited to, mechanical pumps and molecular pumps.

[0049] Helium detection component 30 can refer to a component for detecting helium, first vacuum degree detection component 40 can refer to a component for detecting the vacuum degree of leak detection chamber 10, cryogenic pump body detection component 50 can refer to a component for detecting the cryogenic pump body 220, and helium filling component 60 can refer to a component for filling leak detection chamber 10 with helium.

[0050] The helium concentration detection component 70 can be a component for detecting the helium concentration in the leak detection chamber 10, and can be, but is not limited to, a helium concentration sensor, a gas chromatograph, and a thermal conductivity gas sensor, etc.

[0051] The first calibration component 80 can refer to a component for calibrating the helium concentration inside the leak detection chamber 10. The second calibration component 90 can refer to a component for calibrating the helium concentration inside the cryogenic pump body 220. The first calibration leak hole 82 and the second calibration leak hole 92 are measuring devices used to provide a constant gas leakage rate, primarily for calibrating the sensitivity of the leak detector.

[0052] It should be noted that the cryogenic pump 200 includes a refrigeration unit 210 and a cryogenic pump body 220. The structure and operating principle of the cryogenic pump 200 are known to those skilled in the art and will not be described in detail here.

[0053] When using the cryogenic pump helium mass spectrometry leak detection device 100, first install the cryogenic pump 200's refrigerator 210 and pump body 220 inside the leak detection chamber 10, and then perform leak detection. The specific process is as follows:

[0054] First, perform a leak test on the refrigeration unit 210. The steps for leak testing the refrigeration unit 210 include:

[0055] First, ensure all valves are normally closed and that the first vacuum level detection element 40, the first vacuum pump 24, the helium mass spectrometer leak detector 33, and the refrigerator 210 are in normal working condition. Then, establish a pre-vacuum and open the first valve 22 and the second valve 23 to reduce the vacuum level in the leak detection chamber 10 to a first threshold. Detect the vacuum level in the leak detection chamber 10 using the first vacuum level detection element 40. When the detected vacuum level in the leak detection chamber 10 is less than the first threshold, open the second vacuum pump 25 to reduce the vacuum level in the leak detection chamber 10 to a second threshold, which is less than the first threshold. When the vacuum level in the leak detection chamber 10 reaches the second threshold, the second valve 23 is closed and the third valve 32 is opened simultaneously. The helium information in the leak detection chamber 10 is detected by the helium mass spectrometer leak detector 33. The sixth valve 81 is opened to activate the first calibration leak hole 82, which is used to calibrate the leak detection sensitivity of the helium mass spectrometer leak detector 33. After the leak detection sensitivity is calibrated, the sixth valve 81 is closed, and after the cryogenic pump helium mass spectrometer leak detection device 100 system returns to stability, the stable response value of the helium mass spectrometer leak detector 33 is obtained. The leak rate of the refrigerator 210 is calculated based on the previously measured data. By comparing the calculated leak rate with the standard value, it can be determined whether the refrigerator 210 has a leak.

[0056] Next, leak testing of the cryogenic pump body 220 is performed. The steps for leak testing of the cryogenic pump body 220 include:

[0057] First, close the first valve 22, the third valve 32, the second vacuum pump 25, and the refrigerator 210; open the fifth valve 63 to allow helium in the helium storage unit 62 to fill the leak detection chamber 10, and detect the helium concentration in the leak detection chamber 10 through the helium concentration detection unit 70 until the helium concentration in the leak detection chamber 10 reaches the third threshold before closing the fifth valve 63. Then, a pre-vacuum is established, and the second valve 23 and the fourth valve 54 are opened. The vacuum level inside the cryogenic pump body 220 is detected by the second vacuum level detection element 52. When the vacuum level inside the cryogenic pump body 220 drops to the first threshold, the second vacuum pump 25 is opened to lower the vacuum level inside the cryogenic pump body 220 to the second threshold. When the vacuum level inside the cryogenic pump body 220 reaches the second threshold, the second valve 23 is closed and the third valve 32 is opened. The helium information inside the cryogenic pump body 220 is detected by the helium mass spectrometer leak detector 33. The seventh valve 91 is opened to activate the second calibration leak hole 92 for calibrating the leak detection sensitivity of the helium mass spectrometer leak detector 33. After calibrating the leak detection sensitivity, the seventh valve 91 is closed, and after the cryogenic pump helium mass spectrometer leak detection device 100 system returns to stability, the stable response value of the helium mass spectrometer leak detector 33 is obtained. The leak rate of the cryogenic pump body 220 is calculated based on the previously measured data. By comparing the calculated leak rate with the standard value, it can be determined whether there is a leak in the cryogenic pump body 220.

[0058] In the above technical solution, when detecting leaks in the cryogenic pump 200, the cryogenic pump helium mass spectrometry leak detection device 100 can simulate the cryogenic pump 200 under actual low-temperature operating conditions to perform system-level leak detection, which can accurately capture "cold leaks" and "cold welds" that cannot be detected at room temperature, thereby improving the accuracy of leak detection.

[0059] The cryogenic pump helium mass spectrometry leak detection device 100 according to an embodiment of the present invention, through components such as a leak detection chamber 10, a vacuum pumping assembly 20, a helium detection assembly 30, a first vacuum degree detection element 40, and a cryogenic pump body detection assembly 50, achieves leak detection of the refrigerator 210 and the cryogenic pump body 220 in one device and one vacuum pumping process. It can detect high-pressure helium leaks inside the refrigerator 210, as well as vacuum leaks in the cryogenic pump vacuum chamber and system connection interfaces. Compared with traditional distributed, offline leak detection methods, it can improve leak detection efficiency. Moreover, the detection process can simulate the actual cryogenic operating conditions of the cryogenic pump 200 to perform system-level leak detection, which can improve the accuracy of leak detection. At the same time, the integrated tooling used replaces the bulky and cumbersome traditional helium shroud, which significantly reduces helium consumption and tooling costs, and improves the economy and convenience of operation.

[0060] In some embodiments of the present invention, reference is made to Figure 2 and Figure 3 The leak detection chamber 10 includes a shell 11 and an end cap 12. The top of the shell 11 has an opening 11a, and the end cap 12 is detachably disposed over the opening 11a. The shell 11 is configured to install the cryogenic pump 200 to be tested. In the above technical solution, the end cap 12 is detachably disposed over the opening 11a, facilitating the installation and removal of the leak detection chamber 10, thereby facilitating the entry and exit of the cryogenic pump 200 into and out of the shell 11 and improving the leak detection efficiency of the cryogenic pump 200.

[0061] In some embodiments of the present invention, reference is made to Figure 2 and Figure 3 The end cap 12 is provided with a first hole 12a and a third hole 12b, and the housing 11 is provided with a second hole 11b, a fourth hole, a fifth hole 11d, a sixth hole 11e, and a seventh hole 11f. Among them, the first pipe 21 is installed in the first hole 12a, the first vacuum degree detection element 40 is connected to the second hole 11b, the third pipe 51 is installed in the third hole 12b, the fourth pipe 53 is installed in the fourth hole, the fifth pipe 61 is installed in the fifth hole 11d, the helium concentration detection element 70 is connected to the sixth hole 11e, and the sixth valve 81 is connected to the seventh hole 11f.

[0062] In the above technical solution, the design of the first hole 12a, the third hole 12b, the second hole 11b, the fourth hole, the fifth hole 11d, the sixth hole 11e, and the seventh hole 11f allows each component to pass through the leak detection chamber 10, which facilitates installation and testing. It also prevents external air from entering the leak detection chamber 10, thereby avoiding affecting the test results and improving the reliability of the test.

[0063] In some embodiments of the present invention, reference is made to Figure 2 The hull 11 is provided with an eighth hole 11g and a ninth hole 11h. The compressor 230 of the cryogenic pump 200 is located outside the hull 11. The compressor 230 is provided with an inlet pipe 231 and a return pipe 232. The inlet pipe 231 passes through the eighth hole 11g and is connected to the inlet of the refrigeration unit 210. The return pipe 232 passes through the ninth hole 11h and is connected to the return port of the refrigeration unit 210.

[0064] In the above technical solution, the compressor 230 of the cryogenic pump 200 is located outside the shell 11, which can reduce the impact of the heat generated by the compressor 230 during operation on the internal environment of the leak detection chamber 10, and also facilitates independent maintenance and operation of the compressor 230. The inlet pipe 231 and the return pipe 232 are respectively inserted into the shell 11 through the eighth hole 11g and the ninth hole 11h, ensuring the sealing and stability of the connection between the refrigeration unit 210 and the compressor 230, and preventing external air from entering the leak detection chamber 10 and interfering with the detection results.

[0065] In some embodiments of the present invention, reference is made to Figure 1 The helium filling assembly 60 also includes a pressure reducing valve 64, which is connected in series on the portion of the fifth pipeline 61 located between the helium storage unit 62 and the fifth valve 63.

[0066] In the above technical solution, the pressure reducing valve 64 is connected in series on the part of the fifth pipeline 61 located between the helium storage unit 62 and the fifth valve 63. By adjusting the pressure reducing valve 64, helium enters the leak detection chamber 10 at a stable and appropriate pressure, avoiding detection errors or equipment damage caused by excessive pressure. This ensures the accuracy and reliability of helium concentration detection and also protects the fifth pipeline 61 and related components, extending their service life.

[0067] In some embodiments of the present invention, reference is made to Figure 1 The first vacuum pump 24 is a mechanical pump, and the second vacuum pump 25 is a molecular pump. The first vacuum pump 24, being a mechanical pump, can perform preliminary vacuuming of the leak detection chamber 10, reducing the internal pressure of the leak detection chamber 10 to a certain range. The second vacuum pump 25, being a molecular pump, can further increase the vacuum level inside the leak detection chamber 10 to a higher level, meeting the high vacuum environment requirements of the helium mass spectrometer leak detector 33.

[0068] In some embodiments of the present invention, reference is made to Figure 1Valve 22, valve 23, valve 32, valve 54, valve 63, valve 81, and valve 91 are solenoid valves. In the above technical solution, solenoid valves have the advantages of fast response speed, high control precision, and convenient operation, effectively ensuring the accuracy and timeliness of the on / off states of each pipeline, and improving the stability and reliability of the cryogenic pump 200 detection process. Furthermore, the use of solenoid valves can achieve automated control, reduce errors that may be caused by human intervention, and further optimize leak detection efficiency.

[0069] In some embodiments of the present invention, reference is made to Figure 1 The first vacuum level detection element 40 and the second vacuum level detection element 52 are vacuum gauges. In the above technical solution, the vacuum gauge has the advantages of high measurement accuracy, fast response speed and wide measurement range. The first vacuum level detection element 40 and the second vacuum level detection element 52 are vacuum gauges that can accurately and in real time detect the vacuum level inside the leak detection chamber 10 and the cryogenic pump 200, ensuring that the vacuum level meets the requirements and improving the accuracy of subsequent leak detection results.

[0070] In some embodiments of the present invention, such as Figure 1 As shown, the cryogenic pump helium mass spectrometer leak detection device 100 also includes a computer processing system 101, which processes the acquired data. For example, the computer processing system 101 can be electrically or communicatively connected to the helium concentration detector 70 and the helium mass spectrometer leak detector 33. It should be noted that the structure and operation of the computer processing system 101 are known to those skilled in the art and will not be described in detail here.

[0071] According to an embodiment of the present invention, a leak detection method for a cryogenic pump 200 is also provided. This leak detection method uses the cryogenic pump helium mass spectrometry leak detection device 100 from any of the preceding embodiments to detect leaks in the cryogenic pump 200. For example... Figure 4 As shown, the leak detection method for the cryogenic pump 200 in this embodiment of the invention includes:

[0072] Leak testing of refrigeration unit 210 is performed, and the steps for leak testing of refrigeration unit 210 include:

[0073] Ensure that all valves are in the normally closed state, and that the first vacuum degree detection element 40, the first vacuum pump 24, the helium mass spectrometer leak detector 33 and the refrigerator 210 are in normal working condition.

[0074] The first valve 22 and the second valve 23 are opened to reduce the vacuum level in the leak detection chamber 10 to a first threshold. The vacuum level in the leak detection chamber 10 is detected by the first vacuum level detection element 40. When the vacuum level in the leak detection chamber 10 is detected to be less than the first threshold, the second vacuum pump 25 is turned on to reduce the vacuum level in the leak detection chamber 10 to a second threshold, which is less than the first threshold.

[0075] When the vacuum level inside the leak detection chamber 10 reaches the second threshold, the second valve 23 is closed and the third valve 32 is opened, and the first detection data inside the leak detection chamber 10 is detected by the helium mass spectrometer leak detector 33.

[0076] Open the sixth valve 81 to activate the first calibration leak hole 82 and acquire the first calibration data; close the sixth valve 81 and acquire the first stable data after the cryogenic pump helium mass spectrometer leak detection device 100 system has stabilized.

[0077] The leakage rate of the refrigerator 210 is calculated based on the first detection data, the first calibration data, and the first stability data.

[0078] After the leak detection of the refrigeration unit 210 is completed, the leak detection of the cryogenic pump body 220 is performed. The steps for leak detection of the cryogenic pump body 220 include:

[0079] Close the first valve 22, the third valve 32, the second vacuum pump 25, and the refrigerator 210.

[0080] Open the fifth valve 63 to allow helium in the helium storage unit 62 to fill the leak detection chamber 10. The helium concentration in the leak detection chamber 10 is detected by the helium concentration detector 70 until the helium concentration in the leak detection chamber 10 reaches the third threshold, and then close the fifth valve 63.

[0081] Open the second valve 23 and the fourth valve 54, and detect the vacuum level inside the cryogenic pump body 220 through the second vacuum level detection element 52; when the vacuum level inside the cryogenic pump body 220 drops to the first threshold, open the second vacuum pump 25 to make the vacuum level inside the cryogenic pump body 220 drop to the second threshold.

[0082] When the vacuum level inside the cryogenic pump body 220 reaches the second threshold, the second valve 23 is closed and the third valve 32 is opened, and the second detection data inside the cryogenic pump body 220 is detected by the helium mass spectrometer leak detector 33.

[0083] Open the seventh valve 91 to activate the second calibration leak hole 92 and acquire the second calibration data; close the seventh valve 91 and acquire the second stable data after the cryogenic pump helium mass spectrometer leak detection device 100 system has stabilized.

[0084] The leakage rate of the cryogenic pump body 220 was calculated based on the second detection data, the second calibration data, and the second stability data.

[0085] To facilitate understanding, a specific example can be used for illustration. For instance, the acceptance standard for chiller 210 is that the leakage rate must be less than or equal to 1 × 10⁻⁶. -9 Pa·m 3If the leak rate is within the specified range ( / s), then the refrigeration unit 210 passes the leak test. If the refrigeration unit 210 passes the leak test, the next stage, the cryogenic pump body 220, can proceed to the leak rate test. The acceptance standard for the cryogenic pump body 220 is that the leak rate must be less than or equal to 1×10⁻⁶. -9 Pa·m 3 / s.

[0086] Leak detection sensitivity formula:

[0087]

[0088] Leakage rate calculation formula:

[0089]

[0090] In the formula:

[0091] Q e min Leak detection sensitivity is expressed in Pascals per second (Pa). );

[0092] I n The noise or minimum readable signal of the leak detector, measured in Pascals per second (Pa). );

[0093] Q represents the leak rate of the inspected item, measured in Pascals per second. );

[0094] I 2 represents the stable reaction value of the helium mass spectrometer leak detector 33 during the testing of the inspected part, in Pascals per second (Pa). ) or other relative units;

[0095] I 0 is the background value, and the unit is Pascals per second (Pa). ) or other relative units;

[0096] I 1 represents the stable response value of the leak detector after the leak hole is opened, expressed in Pascals per second (Pa). ) or other relative units;

[0097] The calibration value for calibrating leaks is expressed in Pascals per second (Pa). );

[0098] γ represents the helium concentration (%).

[0099] The first and second test data are in the corresponding formula. I 0 and I n The first calibration data and the second calibration data are given by the formula. I1. The first stable data and the second stable data are given by the formula. I 2.

[0100] For example, during the leak detection phase of the refrigeration unit 210, the first helium concentration value is 99.99%. During the leak detection phase of the cryogenic pump body 220, while recording the second stable data, the precise second helium concentration value at this moment can be read and recorded by the helium concentration detection device 70. The first and second helium concentration values ​​are γ in the leak rate calculation formula.

[0101] It should be noted that the first, second, and third thresholds mentioned above can be adjusted according to the actual situation. For example, refer to... Figure 5 In some implementations, the first threshold is 10 Pa, and the second threshold is 1*10. -2 Pa, the third threshold can be a helium concentration of 50%.

[0102] According to the leak detection method of the cryogenic pump 200 of the present invention, by substituting the first detection data, the first calibration data, the first stabilization data, and the first helium concentration value into the leak rate calculation formula, the computer processing system finally obtains the actual leak rate of the refrigerator 210. Similarly, by substituting the second detection data, the second calibration data, the second stabilization data, and the second helium concentration value into the leak rate calculation formula, the computer processing system finally obtains the actual leak rate of the cryogenic pump body 220, thereby improving detection efficiency and accuracy. Furthermore, during the sequential leak detection of the refrigerator 210 and the cryogenic pump body 220, the leak detection chamber 10 is evacuated only once, further improving leak detection efficiency.

[0103] In some embodiments of the present invention, the first detection data includes the background value and background noise detected in the leak detection chamber 10 by the helium mass spectrometer leak detector 33; the first calibration data is the stable signal value generated by the first calibration leak hole 82; the first stable data is the final value measured after the cryogenic pump helium mass spectrometer leak detection device 100 system has stabilized; the second detection data includes the background value and background noise detected in the cryogenic pump body 220 by the helium mass spectrometer leak detector 33; the second calibration data is the stable signal value generated by the second calibration leak hole 92; the second stable data is the final value measured after the cryogenic pump helium mass spectrometer leak detection device 100 system has stabilized.

[0104] In the above technical solution, during the leak detection stage of the refrigerator 210, the helium mass spectrometer leak detector 33 measures the background value and background noise within the leak detection chamber 10. Combined with the stable signal value from the first calibration leak hole 82 and the final value after stabilization of the cryogenic pump helium mass spectrometer leak detection device 100 system, a complete data chain is formed, effectively eliminating external interference factors and improving the accuracy of leak detection in the refrigerator 210. Similarly, during the leak detection stage of the cryogenic pump body 220, the helium mass spectrometer leak detector 33 detects the background value and background noise within the cryogenic pump body 220. Combined with the stable signal value generated by the second calibration leak hole 92 and the final value after stabilization of the cryogenic pump helium mass spectrometer leak detection device 100 system, external interference factors are effectively eliminated, improving the accuracy of leak detection in the cryogenic pump body 220.

[0105] The following is combined Figures 1 to 3 This describes a specific embodiment of the cryogenic pump helium mass spectrometry leak detection device 100 of the present invention.

[0106] The cryogenic pump helium mass spectrometry leak detection device 100 includes: a leak detection chamber 10, a vacuum pumping assembly 20, a helium detection assembly 30, a first vacuum degree detection element 40, a cryogenic pump body detection assembly 50, a helium filling assembly 60, a helium concentration detection element 70, a first calibration assembly 80, and a second calibration assembly 90.

[0107] The leak detection chamber 10 includes a shell 11 and an end cap 12. The top of the shell 11 has an opening 11a, and the end cap 12 is detachably fitted over the opening 11a. The shell 11 is configured to mount a cryogenic pump 200 to be tested. The end cap 12 has a first hole 12a and a third hole 12b. The shell 11 has a second hole 11b, a fourth hole, a fifth hole 11d, a sixth hole 11e, a seventh hole 11f, an eighth hole 11g, and a ninth hole 11h. A first pipe 21 is installed in the first hole 12a, a first vacuum level detector 40 is connected to the second hole 11b, a third pipe 51 is installed in the third hole 12b, a fourth pipe 53 is installed in the fourth hole, a fifth pipe 61 is installed in the fifth hole 11d, a helium concentration detector 70 is connected to the sixth hole 11e, and a sixth valve 81 is connected to the seventh hole 11f. The compressor 230 of the cryogenic pump 200 is located outside the hull 11. The compressor 230 is equipped with an inlet pipe 231 and a return pipe 232. The inlet pipe 231 passes through the eighth hole 11g and is connected to the inlet of the refrigeration unit 210. The return pipe 232 passes through the ninth hole 11h and is connected to the return port of the refrigeration unit 210.

[0108] The vacuum pumping assembly 20 includes a first pipeline 21, a first valve 22, a second valve 23, a first vacuum pump 24, and a second vacuum pump 25. One end of the first pipeline 21 is connected to the leak detection chamber 10, and the other end is connected to the first vacuum pump 24. In the direction from the leak detection chamber 10 to the first vacuum pump 24, the first valve 22, the second vacuum pump 25, and the second valve 23 are sequentially connected in series on the first pipeline 21. The first vacuum pump 24 is a mechanical pump, and the second vacuum pump 25 is a molecular pump.

[0109] The helium detection assembly 30 includes a second pipeline 31, a third valve 32, and a helium mass spectrometer leak detector 33. One end of the second pipeline 31 is connected to the portion of the first pipeline 21 located between the second vacuum pump 25 and the second valve 23, and the other end is connected to the helium mass spectrometer leak detector 33. The third valve 32 is connected in series on the second pipeline 31. The first vacuum level detection element 40 is a vacuum gauge and is connected to the leak detection chamber 10.

[0110] The cryogenic pump body detection assembly 50 includes a third pipe 51, a second vacuum level detection element 52, a fourth pipe 53, and a fourth valve 54. The second vacuum level detection element 52 is a vacuum gauge. The third pipe 51 is located inside the leak detection chamber 10 and extends to the outside of the leak detection chamber 10, connecting to the second vacuum level detection element 52. The other end of the third pipe 51 inside the leak detection chamber 10 is configured to connect to the cryogenic pump body 220. The fourth pipe 53 is located inside the leak detection chamber 10 and connects to the third pipe 51 at one end, while extending to the outside of the leak detection chamber 10 and connecting to the portion of the first pipe 21 located between the first valve 22 and the second vacuum pump 25. The fourth valve 54 is connected in series on the fourth pipe 53.

[0111] The helium filling assembly 60 includes a fifth pipeline 61, a helium storage unit 62, a fifth valve 63, and a pressure reducing valve 64. One end of the fifth pipeline 61 is connected to the leak detection chamber 10, and the other end is connected to the helium storage unit 62. The fifth valve 63 is connected in series on the fifth pipeline 61. The pressure reducing valve 64 is connected in series on the portion of the fifth pipeline 61 located between the helium storage unit 62 and the fifth valve 63.

[0112] The helium concentration detection element 70 is connected to the leak detection chamber 10; the first calibration component 80 includes a sixth valve 81 and a first calibration leak hole 82 connected to the leak detection chamber 10 through the sixth valve 81.

[0113] The second calibration assembly 90 includes a seventh valve 91 and a second calibration leak 92 that is connected to a third conduit 51 via the seventh valve 91.

[0114] The first valve 22, the second valve 23, the third valve 32, the fourth valve 54, the fifth valve 63, the sixth valve 81, and the seventh valve 91 are solenoid valves.

[0115] In the description of this specification, references to terms such as "some embodiments," "optionally," "furthermore," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0116] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A cryogenic pump helium mass spectrometry leak detection device, characterized in that, include: Leak detection chamber, used to hold the cryogenic pump to be tested; A vacuuming assembly includes a first pipeline, a first valve, a second valve, a first vacuum pump, and a second vacuum pump. One end of the first pipeline is connected to the leak detection chamber, and the other end is connected to the first vacuum pump. In the direction from the leak detection chamber to the first vacuum pump, the first valve, the second vacuum pump, and the second valve are sequentially connected in series on the first pipeline. A helium detection assembly includes a second pipeline, a third valve, and a helium mass spectrometer leak detector. One end of the second pipeline is connected to the portion of the first pipeline located between the second vacuum pump and the second valve, and the other end is connected to the helium mass spectrometer leak detector. The third valve is connected in series on the second pipeline. A first vacuum level detection element is connected to the leak detection chamber; A cryogenic pump body detection assembly includes a third pipeline, a second vacuum level detection element, a fourth pipeline, and a fourth valve. The third pipeline is located inside the leak detection chamber and extends one end to the outside of the leak detection chamber, connecting to the second vacuum level detection element. The other end of the third pipeline inside the leak detection chamber is configured to connect to the cryogenic pump body. The fourth pipeline is located inside the leak detection chamber and connects one end to the third pipeline, while the other end extends to the outside of the leak detection chamber and connects to the portion of the first pipeline located between the first valve and the second vacuum pump. The fourth valve is connected in series on the fourth pipeline. A helium filling assembly, comprising a fifth pipeline, a helium storage unit, and a fifth valve, wherein one end of the fifth pipeline is connected to the leak detection chamber, and the other end is connected to the helium storage unit, and the fifth valve is connected in series on the fifth pipeline; A helium concentration detection device, wherein the helium concentration detection device is connected to the leak detection chamber; The first calibration assembly includes a sixth valve and a first calibration leak hole that communicates with the leak detection chamber through the sixth valve; The second calibration assembly includes a seventh valve and a second calibration leak that connects to the third pipeline via the seventh valve.

2. The cryogenic pump helium mass spectrometry leak detection device according to claim 1, characterized in that, The leak detection chamber includes a shell and an end cap, the top of the shell having an opening, the end cap being detachably disposed over the opening, and the shell being configured for mounting the cryogenic pump to be tested.

3. The cryogenic pump helium mass spectrometry leak detection device according to claim 2, characterized in that, The end cap is provided with a first hole and a third hole, and the chamber is provided with a second hole, a fourth hole, a fifth hole, a sixth hole, and a seventh hole; wherein, the first pipeline is installed in the first hole, the first vacuum degree detection device is connected to the second hole, the third pipeline is installed in the third hole, the fourth pipeline is installed in the fourth hole, the fifth pipeline is installed in the fifth hole, the helium concentration detection device is connected to the sixth hole, and the sixth valve is connected to the seventh hole.

4. The cryogenic pump helium mass spectrometry leak detection device according to claim 2 or 3, characterized in that, The cabin has an eighth hole and a ninth hole. The compressor of the cryogenic pump is located outside the cabin. The compressor has an inlet pipe and a return pipe. The inlet pipe passes through the eighth hole and is connected to the air inlet of the refrigeration unit. The return pipe passes through the ninth hole and is connected to the air return port of the refrigeration unit.

5. The cryogenic pump helium mass spectrometry leak detection device according to claim 1, characterized in that, The helium filling assembly also includes a pressure reducing valve, which is connected in series on the portion of the fifth pipeline located between the helium storage unit and the fifth valve.

6. The cryogenic pump helium mass spectrometry leak detection device according to claim 1, characterized in that, The first vacuum pump is a mechanical pump, and the second vacuum pump is a molecular pump.

7. The cryogenic pump helium mass spectrometry leak detection device according to claim 1, characterized in that, The first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, and the seventh valve are solenoid valves.

8. The cryogenic pump helium mass spectrometry leak detection device according to claim 1, characterized in that, The first vacuum level detection element and the second vacuum level detection element are vacuum gauges.

9. A leak detection method for a cryogenic pump, characterized in that, Leak detection is performed using the cryogenic pump helium mass spectrometry leak detection device as described in any one of claims 1 to 8, the method comprising: The steps for leak detection of the refrigeration unit include: Ensure that all valves are normally closed, and that the first vacuum level detection device, the first vacuum pump, the helium mass spectrometer leak detector, and the refrigerator are in normal working condition; Open the first valve and the second valve to reduce the vacuum level in the leak detection chamber to a first threshold. Detect the vacuum level in the leak detection chamber using the first vacuum level detection device. When the vacuum level in the leak detection chamber is detected to be less than the first threshold, open the second vacuum pump to reduce the vacuum level in the leak detection chamber to a second threshold, which is less than the first threshold. When the vacuum level in the leak detection chamber reaches the second threshold, the second valve is closed and the third valve is opened simultaneously, and the first detection data in the leak detection chamber is detected by the helium mass spectrometer leak detector. Open the sixth valve to activate the first calibration leak and acquire the first calibration data; close the sixth valve and acquire the first stable data after the cryogenic pump helium mass spectrometry leak detection device system has stabilized. The leakage rate of the refrigerator is calculated based on the first detection data, the first calibration data, and the first stability data. After the refrigeration unit leak test is completed, a cryogenic pump body leak test is performed. The steps for the cryogenic pump body leak test include: Close the first valve, the third valve, the second vacuum pump, and the refrigerator. The fifth valve is opened to allow helium from the helium storage device to fill the leak detection chamber. The helium concentration in the leak detection chamber is detected by the helium concentration detector until the helium concentration in the leak detection chamber reaches the third threshold, at which point the fifth valve is closed. Open the second valve and the fourth valve, and detect the vacuum level inside the cryogenic pump body through the second vacuum level detection device; when the vacuum level inside the cryogenic pump body drops to the first threshold, open the second vacuum pump to make the vacuum level inside the cryogenic pump body drop to the second threshold. When the vacuum level inside the cryogenic pump body reaches the second threshold, the second valve is closed and the third valve is opened, and the second detection data inside the cryogenic pump body is detected by the helium mass spectrometer leak detector. Open the seventh valve to activate the second calibration leak and acquire the second calibration data; close the seventh valve and acquire the second stable data after the cryogenic pump helium mass spectrometry leak detection device system has stabilized. The leakage rate of the cryogenic pump body is calculated based on the second detection data, the second calibration data, and the second stability data.

10. The leak detection method for a cryogenic pump according to claim 9, characterized in that, The first detection data includes the background value and background noise detected in the leak detection chamber by the helium mass spectrometer leak detector; the first calibration data is the stable signal value generated by the first calibration leak hole; the first stable data is the final value measured after the cryogenic pump helium mass spectrometer leak detection device system has stabilized. The second detection data includes the background value and background noise detected in the body of the cryogenic pump by the helium mass spectrometer leak detector; the second calibration data is the stable signal value generated by the second calibration leak; the second stable data is the final value measured after the cryogenic pump helium mass spectrometer leak detection device system has stabilized.

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